Using local resources for ruminant feeding is a way to achieve agroecological production in pastoral farming systems. In North Mediterranean countries, sheep farming systems have evolved towards more intensive systems in lowland and hilly areas, whereas remote and rough pastureland is abandoned and local breeds are rarely maintained; rather, they are progressively replaced by highly productive breeds and their crosses. Using the examples of Corsica (France) and Thessaly (Greece), two dairy sheep farming territories developing intensive farming systems that differ in the livestock breeds they use, we explored the hypothesis that the use of local breeds may not be systematically related to the maintenance of pastoral practices in Mediterranean dairy sheep farming systems. For this purpose, three data sets based on interviews with sheep farmers of local breeds and crossbred flocks were analysed in two study areas. The results demonstrated that local breeds’ adaptive abilities can be used in crossbred flocks or purebred flocks to maintain a feeding system based on pastoral components. However, other drivers also appear to lead into the declining use of local pastoral resources. Apart from the use of local breeds, year-to-year adjustments of replacement and culling rates sometimes have to be applied in order to address the inter-annual variations of the fodder on offer. This paper provides an original approach to studying the link between local breeds and the pastoral components of farming systems by combining synchronic and diachronic analyses of the practices in crossbred and purebred flocks composed of local breeds.